(a) Field of the Invention
This invention relates to a cable cutter for cutting heavy duty cable and more particularly, but not by way of limitation, to a safety cable cutter using centrifugal force for cutting the cable. The cable used for lowering various types of service equipment down an existing oil and gas well.
(b) Discussion of Prior Art
In servicing an oil and gas well having various depths of 500 to 1000 feet and greater, heavy wire cable is coiled typically in twenty foot coils next to a well head. An end of the cable is attached to different types of service equipment, such as an electric motor with pump, and then lowered downwardly into the well bore. Should the equipment with cable attached thereto begin to free fall down the well bore, the coils of cable will begin to fly randomly and dangerously next to the well head presenting a great safety risk to a well service company employee working in the well head area. The subject safety cable cutter is designed to eliminate this potential safety risk.
Heretofore, there have been a variety of different types well service equipment used for serving an oil and gas well down hole. For example, in U.S. Pat. No. 4,512,411 to Pringle, a well service line cutter is disclosed having a down hole energy chamber holding a pressurized gas. When a hydraulic controlled valve is opened in the energy chamber, a piston with cutters move into the well bore for cutting any line in the well. In U.S. Pat. No. 4,738,312 to Wittrisch, a cable cutting coupling inside the well is described. The coupling includes a tubular body with a slide. The slide includes a severing member for cutting the cable when it is moved from a first position to a second position inside the tubular body. In U.S. Pat. No. 4,886,115 to Leggett et al., a wireline safety mechanism with a tubular body is disclosed mounted between a lubricator and a stuffing box of a wireline assembly. A wireline cutter is mounted inside the tubular body to cut the wireline and release a wireline blowout tool string that is stuck and blocking a wellhead safety valve and blowout preventor.
None of the above mentioned prior art patents specifically disclose the unique features, structure and function of the subject safety cable cutter placed next to a well head and used to cut a service cable when it begins to free fall down a well bore.